Non-adjustable encapsulated buzzer



Oct. 27, 1970 P. A. DOLTER ETA!- 3,533,104v

NON-ADJUSTABLE ENCAPSULATED BUZZER Filed Nov. 20, 1968 VINVENTORS PAUL 4. 0x752 W 0: 6' l /A/KERTQA/ BY I ATTORNEYS United States Patent O 3,537,104 NON-ADJUSTABLE ENCAPSULATED BUZZER Paul A. Dolter, Roselle, and Neil C. Pinkerton, Palatine, Ill., assignors to The Dole Valve Company, Morton Grove, Ill., a corporation of Illinois Filed Nov. 20, 1968, Ser. No. 777,217 Int. Cl. G08b 3/10 US. Cl. 340384 4 Claims ABSTRACT OF THE DISCLOSURE A non-adjustable buzzer wherein the sounding elements are completely encapsulated and, therefore, isolated from their working environment, and wherein the buzzer comprises a single spring-biased movable operating element.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to electromagnetically operated sound producing devices and in particular to non-adjustable electromagnetically operated buzzer devices.

Description of the prior art Heretofore, it was the general practice to provide a. buzzer device with an electromagnetically operated member which strikes another member or members within a housing which is essentially opened to the environment of the device. In environments containing dust, water vapor, or other contaminants which may be detrimental to the operation of the buzzer, such devices are prone to failure or require maintenance to keep the operating members free of contaminants. In addition, prior buzzer devices utilized a variety of apparatus for mounting the sounding elements in juxtaposition.

The present invention overcomes the above disadvantages of a contaminated environment and provides a buzzer structure which is completely encapsulated, and which employs only a single moving part in its construction, the construction ibeing simple and requiring no maintenance thereof.

SUMMARY OF THE INVENTION According to the invention, a non-adjustable buzzer device is realized by providing within an electromagnetic structure which is hermetically sealed to a mounting base, a slidably disposed plunger which is resiliently biased against the head of a rivet extending through the plunger and secured to the base. The electromagnetic device comprises a hollow bobbin onto which is wound an energizing coil and which has angularly extending grooves in its flange portions for sealing the coil with an encapsulating material. Further, means are provided for indexing the bobbin and the base as an aid in assembling the buzzer device.

BRIEF DESCRIPTION OF THE DRAWINGS The invention, its construction and operation will be best understood by reference to the following detailed description of a single illustrative embodiment of the invention taken in conjunction with the drawings, in which:

FIG. 1 is a top plan view of a non-adjustable buzzer constructed in accordance with the principles of the invention; and

FIG. 2 is an elevational view, partially in section, taken along the line II-II of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings, a non-adjustable buzzer is shown generally at as comprising a base plate 111 made from a 3,537,104 Patented Oct. 27, 1970 metal, such as steel, and which has through processes, such as punching and embossing, has been provided with an aperture 12, an edge indentation 13, a lug 14, an edge indentation 15 and an upstanding embossment 16 having an aperture 17 therein. A bobbin 18 of insulating material has a winding 28 thereon between its spaced end flanges 19 and 20. The flanges 19 and 20 include a plurality of angular grooves therein defined by edges 21, 22; 23, 24; and 25, 26 for receiving an encapsulating material 27 in sealing engagement with the bobbin, and the indentation in base 15 further receives a protrusion 29 of encapsulating material 27 as a portion of means for indexing the electromagnetic structure to the base plate H. The remainder of this indexing is accomplished by the upstanding embossment 16 which extends into the bore 30 of the bobbin 18. The winding 28 is connected to receive energizing power, for example, volt 50/ 6 0 c.p.s., froma commercial or equivalent supply through the connecting terminals 31 and 32.

Disposed in the central bore 30 of bobbin 18 is a hollow magnetically sensitive plunger 31, having a bore 32 and a counterbore 33 at its lower end for receiving a biasing spring 34. Disposed through the center bore 32 of the hollow plunger 31 is a rivet 35, preferably of copper or aluminum, including a head portion 36, a shank portion 37, and a restricted portion 38 which is received by aperture 17 of embossment 16 on base plate 11. The restricted portion 3-8 of rivet 35 is set, or is spun-over, to form a locking arrangement 39 with the concave portion of embossment 16.

It will be noted that the plunger 31 is locked in place by the rivet 35 and bears against the head 36 of rivet 35. A gap 40 exists between the base plate 111 and the lower end of plunger 31. Upon the alternating energization of coil 28, plunger 31 is forced against and away from the upper surface of base plate 11 at 'embossment 16 and the head 36 of rivet 35, the striking of the base embossment 16 of plate 11 and the striking of the head 36 of rivet 35 eifecting the emission of buzzing sound.

Advantageously, the length and mass of plunger 31, and the spring 34, may be selected to determine the output level of the buzzer. Additionally, the depth of embossment 16 may be selected to determine the air gap 40 and accordingly the output level of the buzzer.

While we have described our invention by specific reference to a single illustrative embodiment thereof, many changes and modifications of our invention will become apparent to those skilled in the art and such changes and modifications should be included within the spirit and scope of the invention as set forth in the appended claims.

What we claim as our invention is:

1. An electromagnetic buzzer device for operation on alternating current comprising:

a base having an aperture therein,

a bobbin carried on said base, said bobbin having a bore therethrough,

a winding on said bobbin for receiving alternating current,

said winding establishing an alternating magnetic field upon receipt of alternating current,

a plunger slidably disposed in the bore of said bobbin and slidable along its longitudinal axis in response to an alternating magnetic field, said plunger having a bore therethrough,

means extending through the bore of said plunger and the aperture of said base and bearing against said bobbin and said base for securing said bobbin to said base, and spring means disposed between said plunger and said base for urging said plunger away from said base.

2. The buzzer device according to claim '1, comprising means for indexing said bobbin to said base, said indexing means including an upstanding embossment on said base 4. The buzzer device according to claim 2, further having the aperture of the base therein, said-embossment comprising a plurality'of electrical terminals secured in extending into the bore of said bobbin, a recessed edge portion included in said base, and encapsulating means covering said bobbin and said winding and including a protrusion extending into said recess portion of said base.

3. The buzzer device accordingto claim 2, wherein said bobbin includes a pair of flange portions spaced apart by a spool portion carrying said winding, said flange portions including means forming annular grooves therein for, receiving the material of said encapsulating means to seal said winding between said bobbin and said encapsulating means.

said encapsulating means and connected to said winding.

References Cited UNITED STATES PATENTS 2,913,715 11/1959 Myrgren 340-384 HAROLD I. PITTS, Primary Examiner j US. Cl. X.R. 

